JP2017200721A - Method for hard-precision machining tooth portion of gear or tooth portion of workpiece with gear-like contour - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a working method which avoids defects in correction in a precision grinding process or between precision grinding processes, and can obtain improvement of surface quality of a tooth portion and a gear-like contour.SOLUTION: A working method includes: a) a step of providing a hard-precision machining tool 3 having machining zones 4 and 5 adjacent to at least two axial directions, where the first machining zone 4 is designed so as to grind a tooth portion 1 of a gear 2, and the second machining zone 5 is designed so as to precision grind and/or polish the gear portion; b) a step of grinding the gear portion of the gear by the first machining zone, where a first turn angle βexists between a rotation shaft a and a rotation shaft b of the hard-precision machining tool; and c) a step of precision grinding and/or polishing the gear portion of the gear by the second machining zone, where a second turn angle different from the first turn angle exists between the rotation shaft of the gear and the rotation shaft of the hard-precision machining tool.SELECTED DRAWING: Figure 2

Description

  The present invention relates to a method for hard precision machining of a gear tooth or a gear tooth of a workpiece having a gear-like profile, the gear or workpiece having a rotating shaft, in which the gear tooth or The teeth of the gear-shaped workpiece are machined by a hard precision machining tool, which has a rotating shaft and rotates around the rotating shaft during hard precision machining. To do.

  The final grinding process is of great importance, especially in the production of gears. In this process, the side surfaces of the teeth are subjected to a grinding operation such that the side surfaces are accurately shaped. Efficient processes in tooth production are generative grinding with a grinding worm or contour grinding with a contour grinding wheel.

  A method of the type described above is known from German patent application 102010005435A1. In U.S. Pat. No. 6,053,086, rough machining is first performed on the workpiece to machine teeth that are located in the surface area of the workpiece, and then finishing machining is performed on the workpiece. To avoid, it is swung between two process steps. Further, as solutions known in advance, those disclosed in WO94 / 19135A1 pamphlet (Patent Document 2), US Pat. No. 6,402,607B2 (Patent Document 3), and US Pat. No. 3,708,925 (Patent Document 4). There is.

  In addition to the grinding process itself, it is known to later perform a precision grinding or polishing process in order to optimize the side surfaces of the teeth. Such a precision grinding process or polishing process is also referred to as an abrasive grinding process, which is a subsequent machining finishing process, which can improve the quality of the tooth surface. . The aim of machining in the precision grinding or polishing process is to improve the surface quality and contact ratio of the tooth side surface with a very small removal amount.

  Thereby, a multi-step process is employed, in which a conventional generative grinding or contour grinding process is first carried out, followed by the aforementioned precision grinding or abrasive grinding. Thereby, two different tool specifications are used, which differ slightly or slightly from each other with respect to the shape or contour of the tools. Often, both the area for productive grinding or contour grinding on the one hand and the area for precision grinding or abrasive grinding on the one hand are one, and are arranged on the same tool carrier and firmly connected to each other. (Eg glued or screwed). Preferably, both machining zones are then collectively finished first (in the case of a finishable tool). Subsequently, each of the precision grinding tool and the polishing tool can also be changed slightly by further copying. Thereby, for example, a reduction in the outer diameter can occur. In the subsequent machining, the two zones mentioned are then used continuously, but in principle the same tool settings and in particular the same swivel angle of the tool are used.

  Thereby, correction can be realized in precision grinding and polishing grinding, respectively. What is known about the correction is to pivot the workpiece axis to reduce the feed rate and polishing pressure on one of the tooth sides, respectively, and to reduce the feed rate and polishing pressure on the other side. Increasing and simultaneously changing the distance of the axis, which then acts equally on both tooth sides in a symmetrical profile.

  However, often in a disadvantageous manner, the roughness at the tip and base of the tooth is different from that which is undesirable. This problem can be solved only to a limited extent by the previously known possibilities for correction. Thus, for example, reducing the axial distance can increase machining forces and cause undesirable inconsistencies in shape.

  Moreover, disadvantageously, the known solutions are very time consuming due to the various work steps required for setup and often do not reach the desired results.

  Moreover, disadvantageously, the results obtained are often compromised with respect to the tooth-side geometry created.

German Patent Application No. 102010005435A1 International Publication No. 94 / 19135A1 Pamphlet US Pat. No. 6,402,607 B2 U.S. Pat. No. 3,708,925

  The object of the present invention is therefore to provide a method of the kind described above, by means of which it is possible to obtain improved surface quality of the tooth part and the gear-like profile, respectively. Thereby, the above-mentioned drawbacks in the correction during the precision grinding process or the abrasive grinding process should be avoided, so that the desired tooth side geometry is accurately obtained.

The solution of this object according to the invention is characterized by the following method, which comprises:
a) providing a hard precision machining tool comprising at least two axially adjacent machining zones, wherein the first machining zone comprises a gear tooth or a gear tooth profile workpiece tooth; Designed for grinding and the second machining zone is designed for precision grinding and / or polishing of teeth or gear-like contours;
b) Grinding the gear teeth or the gear teeth of the workpiece with the first machining zone of the hard precision machining tool, the rotation axis of the gear or workpiece and the hard precision machining A first swivel angle exists between the rotation axis of the tool, and
c) the subsequent step of precision grinding and / or polishing of the gear teeth or the gear teeth of the workpiece with a second machining zone of a hard precision machining tool, A second turning angle different from the first turning angle exists between the rotating shaft and the rotating shaft of the hard precision machining tool; and
Is provided.

  Preferably, a worm-like tool is used as the hard precision machining tool. Alternatively, a disk-shaped tool can be used as the hard precision machining tool.

  Preferably, a tool capable of further finishing is used as the hard precision machining tool.

  Preferably, the contour of the hard precision machining tool is the same in the first machining zone and the second machining zone.

  As the hard precision machining tool, a tool containing an abrasive in the substrate can be used, but the elastic modulus of the substrate material in the first machining zone and the second machining zone is different. Preferably, the elastic modulus of the substrate material in the first machining zone is higher than in the second machining zone. Specifically, according to one embodiment of the present invention, it is provided that a tool is used as a hard precision machining tool, the tool having a substrate made of a ceramic material in a first machining zone. And having a substrate comprising a plastic material, in particular polyurethane, in the second machining zone. Moreover, the tool is more elastic in the second zone, which can be advantageous for abrasive grinding.

  Characteristic diagrams or formula relationships can be stored in the machine controller, which provides or enables the following calculations or simulations. The calculation or simulation is the first for a given diameter of a hard precision machining tool and for the desired amount of removal on the side of the tooth or gear profile during step c) above. Calculating or simulating the angular difference between the first turning angle and the second turning angle. Specifically, the following can be provided. That is, in the execution of the above step c), the required angle difference between the first turning angle and the second turning angle is recalled from the characteristic diagram or the official relationship, calculated or simulated, and the tooth This is achieved in accordance with the specifications regarding the desired removal amount at the side of the part or gear-like profile.

  To date, the present invention uses the tool turning angle as a possible correction in the above sense. If the theoretically calculated swivel angle (which is used for pre-machining (and hence generative grinding or contour grinding)) is now deviated, the swivel angle correction is And for abrasive grinding respectively (and thus in abrasive grinding).

  Thereby, depending on the diameter of the tool, the desired specification (i.e. the amount of removal from the side of the tooth and from the contour, respectively, given in micrometers) can be adjusted within the swivel angle correction (in degrees). It is possible to convert and then calculate using the theoretical swivel angle.

  By so correcting the swivel angle of the tool, it becomes easier to increase the polishing pressure during precision grinding or grinding and in that situation the shape at the tooth tip and base or even different values. It has been found that there is no adverse deviation in the roughness of. Therefore, the process parameters can be easily set, and the quality of the tooth portion and the contour is improved.

  Thus, according to the proposed concept, during the precision grinding or polishing process (according to the second machining zone of the tool), the turning angle of the grinding head is determined by grinding or pre-processing (according to the first machining zone of the tool). Compared to machining, this is a change, whereby the pressure of the tool on the side of the tooth is changed and therefore the removal amount is affected.

  However, tolerances in the tooth or contour shape can be maintained in an improved manner since the radial effect of the tool on the workpiece remains unchanged.

  The proposed method is appropriate for precision grinding and polishing of gears and special contours, respectively.

  In the drawings, an embodiment of the invention is shown.

FIG. 1 shows a side view of a worm-shaped tool. FIG. 2 shows a side view of the tool according to FIG. 1 meshing with a gear during productive grinding. FIG. 3 shows a side view of the tool according to FIG. FIG. 4 shows a head curve, from which the required change in swivel angle results in a dependence on the desired removal rate for different diameters of the grinding worm.

  It has been found that if gearbox oil with reduced tooth side surface roughness and low viscosity is used, it is possible to increase the degree of efficiency of the transmission without the drawbacks of stability. It was done. The basis for this is research in transmissions that have been produced by seismic grinding as a finishing process. However, particularly from the perspective of the gear producer, this method is not suitable for integration into an automated process chain. Therefore, the following has been investigated and shown: That is, finishes with Rz equal to 1 μm or less than 1 μm can be produced by integrating a precision grinding process on a conventional gear grinding machine. Modern machines of this kind offer the possibility of using precision grinding techniques in contour grinding as well as in generative grinding.

  In contour grinding, a precision grinding wheel is first used in addition to a conventional grinding wheel, which may be finishable or may not include a finish. Both tools can be attached to the same tool mandrel. After the conventional grinding process is finished, the desired high quality finish is produced in a further grinding process using precision grinding wheels at the same tightening.

  In the field of mass production of gears, continuous generative grinding is most often used because of its advantageous productivity. By using a combined tool consisting of a conventional tool and a precision grinding tool in one tightening, it is possible to produce gears with a finishing quality (Rz) in the range of less than 1 μm. Thereby, the additional work required is usually only less than 50% of the machining time of the conventional grinding process.

  According to this embodiment, the hard precision machining tool 3 which is a grinding worm is used. This serves as a combination of productive grinding followed by precision grinding or polishing grinding. To do so, the hard precision machining tool 3 has a first machining zone 4 and a second machining zone 5. The first machining zone 4 serves for productive grinding, while the second machining zone 5 serves for abrasive grinding. In the present case, the hard precision machining tool 3 is a finishable tool, i.e. the contour 6 of the tool is created by a finishing process. Furthermore, in this case it is provided that the worm-shaped contour 6 is identical in both zone 4 and zone 5.

  However, it can be provided that the carrier material and the base material of the tool 3 are different in the two zones 4 and 5 respectively. In the grinding worm zone 4 a traditional ceramic material with abrasive is used, whereas in the grinding worm zone 5 there is a softer material or more flexible, for example polyurethane. It is possible to use a certain material (specifically, a material having a lower elastic modulus), so that the tool 3 here has a higher degree of elastic modulus, which is abrasive grinding. Can be advantageous.

  During machining, the hard precision machining tool 3 rotates around the rotation axis b. Apart from that, the hard precision machining tool has a diameter D.

  In FIG. 2 and FIG. 3, the process situation is schematically shown during productive grinding (FIG. 2) and subsequent abrasive grinding (FIG. 3). According to this, the following can be seen. That is, in a known manner, during hard precision machining, the hard precision machining tool 3 meshes with a workpiece in the form of a gear 2 to be machined, ie meshes with the tooth 1 of the gear 2. The gear 2 rotates about its axis of rotation, while the hard precision machining tool 3 rotates about its axis of rotation b.

As can be seen in FIG. 2, for generative grinding, the first sub-step of hard precision machining, the first machining zone 4 of the hard precision machining tool 3 is used, where the gear 2 Between the rotation axis and the rotation axis b of the hard precision machining tool 3 is given a first swivel angle β ₁ (what is shown in the figure and indicated by β is, after all, It is a complementary angle for 90 °. This swivel angle β ₁ relates to a certain theoretical angle, which is the difference between the workpiece axis and the tool axis in order to ideally produce the desired profile using generative grinding. This is something that must be given in between

According to FIG. 2, after the productive grinding has been carried out, the abrasive grinding continues, which is the second step and the final sub-step of hard precision machining. To do so, the second machining zone 5 of the hard precision machining tool 3 is used. The following is very important: That is, now again, a turning angle is provided between the rotating shaft of the gear 2 and the rotating shaft of the hard precision machining tool 3, and this turn angle is now the second turning angle β _2. The second turning angle β ₂ is different from the first turning angle β _1, and therefore different from the ideal turning angle, but the ideal turning angle is the ideal geometric shape of the tooth portion 1. It must be given when it is polished.

Since the second turning angle β ₂ deviates from the first turning angle β ₁ , and therefore, the angle difference Δβ is given, the additional removal amount Δs is removed from the tooth side surface of the tooth portion 1. As a result.

This situation is shown in FIG. Here, the removal amount Δs is indicated by the dependency on the angle difference Δβ, that is, for the different diameters D of the grinding worm 3. Thereby, the diameter D ₁ is the smallest diameter of the grinding worm 3 and the diameter D ₄ is the largest diameter of the grinding worm 3. The characteristic curves shown in FIG. 4 can be stored in the machine controller, or can be calculated and simulated respectively in the machine controller using the stored formulas, resulting in: After productive grinding, it is possible to access the machine controller when abrasive grinding has to be performed. For a known diameter and a predetermined diameter D of the (polishing) grinding worm, it is immediately determined how much the angle difference Δβ should be relative to the desired removal amount Δs in order to obtain the desired result. It is possible. The angular difference required for abrasive grinding can therefore be stored directly as a set of curves for special application in a machine controller. Also, the angular difference is calculated in the machine controller using a predetermined variable (worm diameter, desired removal amount) or calculated using simulation, and then the determined angular difference is Used for abrasive grinding.

  In this embodiment, a two-part grinding worm 3 is employed, the grinding worm being contoured on one side by one and the same finishing tool.

1 Tooth part / Gear-shaped contour 2 Gear / Workpiece 3 Hard precision machining tool (grinding worm)
4 First machining zone 5 Second machining zone 6 Outline of hard precision machining tool a Gear rotation axis / workpiece rotation axis b Hard precision machining tool rotation axis β ₁ First turning angle β ₂ 2 Turning angle Δβ Angle difference D Diameter of hard precision machining tool Δs Removal amount

Claims (10)

A method for hard precision machining of a tooth portion (1) of a gear (2) or a tooth portion (1) of a gear-shaped workpiece, wherein the gear (2) or the workpiece is a rotating shaft (a And the tooth portion (1) of the gear (2) or the tooth portion (1) of the workpiece of the gear-like contour is machined by a hard precision machining tool (3) Wherein the hard precision machining tool (3) has a rotation axis (b) and rotates around the rotation axis (b) during hard precision machining,
The method
a) providing a hard precision machining tool (3) comprising at least two axially adjacent machining zones (4, 5), the first machining zone (4) comprising said gear (2 ) Of the toothed portion (1) or the toothed portion (1) of the workpiece of the gear-like profile, and the second machining zone (5) is the toothed portion (1) or Designed for precision grinding and / or polishing of said gear-like profile;
b) The tooth portion (1) of the gear (2) or the tooth portion (1) of the workpiece with the gear-shaped contour is moved to the first machining zone (4) of the hard precision machining tool (3). 1) between the rotating shaft (a) of the gear (2) or the workpiece and the rotating shaft (b) of the hard precision machining tool (3). A step in which there is a turning angle (β ₁ );
c) The tooth portion (1) of the gear (2) or the tooth portion (1) of the workpiece with the gear-shaped contour is moved to the second machining zone (5) of the hard precision machining tool (3). ), And the rotating shaft (a) of the gear (2) or the workpiece and the rotating shaft (b) of the hard precision machining tool (3). There is a second turning angle (β ₂ ) different from the first turning angle (β ₁ ),
A method comprising: The method of claim 1, comprising:
A method characterized in that a worm-like tool is used as the hard precision machining tool (3). The method of claim 1, comprising:
A method, characterized in that a disk-shaped tool is used as the hard precision machining tool (3). A method according to any one of claims 1 to 3, comprising
A method characterized in that a finishable tool is used as said hard precision machining tool (3). A method according to any one of claims 1 to 4, comprising
Method, characterized in that the contour (6) of the hard precision machining tool (3) is the same in the first machining zone (4) and the second machining zone (5). A method according to any one of claims 1 to 5, comprising
As the hard precision machining tool (3), a tool containing an abrasive in a substrate is used, and the material of the substrate in the first machining zone (4) and in the second machining zone (5) A method characterized in that the elastic moduli of are different. The method of claim 6, comprising:
Method according to claim 1, characterized in that the elastic modulus of the substrate material in the first machining zone (4) is higher than in the second machining zone (5). The method of claim 7, comprising:
The hard precision machining tool (3) has a substrate made of a ceramic material in the first machining zone (4) and a substrate comprising a plastic material, in particular polyurethane, in the second machining zone (5). A method, characterized in that a tool is used. A method according to any one of claims 1 to 8, comprising
A characteristic diagram or a formal relationship is stored in a machine controller, which is configured to provide the first turning angle (β ₁ ) and the second for a given diameter (D) of the hard precision machining tool (3). Desirable removal on the side of the tooth (1) or the gear-like profile during the calculation or simulation of the angle difference (Δβ) with respect to the turning angle (β ₂ ) and step c) according to claim 1 A method characterized in that it provides or enables the calculation or simulation of a quantity (Δs). The method of claim 9, comprising:
In performing step c) according to claim 1, it is required between the first turning angle (β ₁ ) and the second turning angle (β ₂ ) from the characteristic diagram or the official relationship. The angular difference (Δβ) is recalled, calculated or simulated and realized according to the specification of the desired removal amount (Δs) on the side of the tooth (1) or the gear-like profile ,Method.

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